Update on current TAVI technology, indications, screening, and outcomes

Abstract

Transcatheter aortic valve replacement (TAVI) is an established treatment for inoperable patients or patients at high surgical risk with severe aortic stenosis. Herein, we illustrate the key design features of the main new generation devices that are entering contemporary clinical practice, the labeled and off-labeled indications, the basic principles of screening process, and the clinical outcomes of the TAVI procedure.Answer questions and earn CME: https://wileyhealthlearning.com/Activity2/ 4193543/Activity.aspx TAVI New TechnologyDespite growing experience with transcatheter aortic valve replacement (TAVI) the first-generation devices were associated with several limitations such as: valve malpositioning, vascular complications, paravalvular regurgitation (PVR), and conduction disorders [1,2]. Several new generation TAVI devices (Table 1), aimed at addressing these issues. Medtronic Evolut-R TMThe Evolut-R TM is the new iteration of the Medtronic CoreValve â (MCV), ( Figure 1A). Several key features of the MCV have been preserved, namely the trileaflet porcine pericardial tissue, the supra-annular position of the valve leaflets, the self-expanding nitinol stent frame and the architecture in three levels of function: inflow portion with a high radial force for anchoring within the aortic annulus, mid portion with a constrained structure for preservation of the coronary flow, and outflow portion with a high hoop strength for coaxiality with the aortic root. However, the new generation Evolut-R TM presents several improvements namely:) the inflow portion is wider and more cylindrical providing a flatter landing zone to ensure maximum over-sizing within the full target implant depth range, (iii) the geometry of the distal diamond cell of the inflow portion has been modified with a slightly asymmetric configuration and extended length for better conformability and consistent radial force across a range of annulus sizes, (iv) the distal skirt has been extended with a scalloped design creating a longer landing zone for better sealing, (v) the prosthesis is fully repositionable and retrievable before final detachment of the hooks (up to three times) and, (vi) the 14 Fr profile of the delivery system (true outer diameter 18 Fr), with the option of proceeding to sheath-less procedures reduces the rate of vascular complications. At the moment the device is available in three sizes (23, 26, and 29 mm) covering aortic annuli from 18 to 26 mm. In addition, whereas positioning of the actual MCV can be sometimes challenging, the 1:1 ratio applied to the handle and prosthesis unsheathing-resheathing response aims at ª 2016 Hellenic College of Cardiology

TAVI and the future of aortic valve replacement

“…16 In concordance with the clinical and anatomical considerations discussed in Table 1, the recent EACTS and American Heart Association (AHA) guidelines agree that the main recommendations for TAVI in patients with severe aortic stenosis must have the T A B L E 1 Considerations made for the decision between TAVI and SAVR in patients with severe aortic stenosis (based on the 2017 European Association for Cardio-thoracic Surgery guidelines on the management of valvular heart disease) following two indications: a life expectancy greater than 1 year and representing a high surgical risk. 17 However, in the presence of trials encouraging surgical intervention for severe aortic valve disease with good long-term results, Akin et al 18 suggested an algorithm to determine the most suitable treatment intervention for patients with severe aortic stenosis, Figure 1.…”

Post-TAVI Follow-Up with MDCT of the Valve Prosthesis: Technical Application, Regular Findings and Typical Local Post-Interventional Complications

“…The Lotus prosthesis from Boston Scientific also consists of a nitinol frame with a round shape when expanded and valve leaflets of bovine pericardium. A flexible polyurethane/polycarbonate seal around the lower half of the stent frame (adaptive seal) prevents paravalvular leaks [9]. In contrast to the other two prostheses, the Lotus valve prosthesis is expanded mechanically via three arms and not automatically or via balloon catheter.…”

“…This allows relatively controlled insertion of the valve and also the option of retrieving and repositioning the valve even after complete expansion. An additional radiopaque tantalum marker in the center of the stent frame facilitates positioning of the valve [9]. During expansion of the stent, the stent frame shortens and the marker moves in the direction of the annulus until it reaches the correct position at the level of the sinus of Valsalva, approx.…”

“…Occlusion of the coronary ostia due to a particularly high stent position is very rare since only the lower stent portions are covered in the Edwards SAPIEN and Lotus prostheses and there is significant tapering at the level of the coronary ostia in the case of the CoreValve prosthesis [4,9,12]. Occlusion of the ostia can be caused not only by the stent but also by positioning of the original calcified valves in front of the ostium, an aortic dissection with involvement of the coronary artery, or embolization of calcium or deposits on the old aortic valve into the coronary arteries.…”